Refactor and fix argument handling

- Move all Typst arguments into the respective Args methods the Options* types
- Simplify the logic in the Caller implementations
- Add docker volume handling for other commands than compile
- Get rid of options_test.go as its test got replaced with the TestCLI_FontsWithFontPaths test

cli.go

@@ -64,12 +64,11 @@ func (c CLI) Fonts(options *OptionsFonts) ([]string, error) {
 		return nil, fmt.Errorf("not supported on this platform")
 	}
 
-	args := []string{"fonts"}
+	if options == nil {
-	if options != nil {
+		options = new(OptionsFonts)
-		args = append(args, options.Args()...)
 	}
 
-	cmd := exec.Command(execPath, args...)
+	cmd := exec.Command(execPath, options.Args()...)
 	cmd.Dir = c.WorkingDirectory
 
 	var output, errBuffer bytes.Buffer
@@ -97,12 +96,6 @@ func (c CLI) Fonts(options *OptionsFonts) ([]string, error) {
 // Compile takes a Typst document from input, and renders it into the output writer.
 // The options parameter is optional, and can be nil.
 func (c CLI) Compile(input io.Reader, output io.Writer, options *OptionsCompile) error {
-	args := []string{"c"}
-	if options != nil {
-		args = append(args, options.Args()...)
-	}
-	args = append(args, "--diagnostic-format", "human", "-", "-") // TODO: Move these default arguments into OptionsCompile
-
 	// Get path of executable.
 	execPath := ExecutablePath
 	if c.ExecutablePath != "" {
@@ -112,7 +105,11 @@ func (c CLI) Compile(input io.Reader, output io.Writer, options *OptionsCompile)
 		return fmt.Errorf("not supported on this platform")
 	}
 
-	cmd := exec.Command(execPath, args...)
+	if options == nil {
+		options = new(OptionsCompile)
+	}
+
+	cmd := exec.Command(execPath, options.Args()...)
 	cmd.Dir = c.WorkingDirectory
 	cmd.Stdin = input
 	cmd.Stdout = output

docker.go

@@ -38,14 +38,32 @@ type Docker struct {
 // Ensure that Docker implements the Caller interface.
 var _ Caller = Docker{}
 
-// VersionString returns the Typst version as a string.
+// args returns docker related arguments.
-func (d Docker) VersionString() (string, error) {
+func (d Docker) args() []string {
 	image := DockerDefaultImage
 	if d.Image != "" {
 		image = d.Image
 	}
 
-	cmd := exec.Command("docker", "run", "-i", image, "--version")
+	// Argument -i is needed for stdio to work.
+	args := []string{"run", "-i"}
+
+	// Add mounts.
+	for _, volume := range d.Volumes {
+		args = append(args, "-v", volume)
+	}
+
+	// Which docker image to use.
+	args = append(args, image)
+
+	return args
+}
+
+// VersionString returns the Typst version as a string.
+func (d Docker) VersionString() (string, error) {
+	args := append(d.args(), "--version")
+
+	cmd := exec.Command("docker", args...)
 
 	var output, errBuffer bytes.Buffer
 	cmd.Stdout = &output
@@ -66,15 +84,12 @@ func (d Docker) VersionString() (string, error) {
 // Fonts returns all fonts that are available to Typst.
 // The options parameter is optional, and can be nil.
 func (d Docker) Fonts(options *OptionsFonts) ([]string, error) {
-	image := DockerDefaultImage
+	args := d.args()
-	if d.Image != "" {
-		image = d.Image
-	}
 
-	args := []string{"run", "-i", image, "fonts"}
+	if options == nil {
-	if options != nil {
+		options = new(OptionsFonts)
-		args = append(args, options.Args()...)
 	}
+	args = append(args, options.Args()...)
 
 	cmd := exec.Command("docker", args...)
 
@@ -103,28 +118,14 @@ func (d Docker) Fonts(options *OptionsFonts) ([]string, error) {
 // Compile takes a Typst document from input, and renders it into the output writer.
 // The options parameter is optional, and can be nil.
 func (d Docker) Compile(input io.Reader, output io.Writer, options *OptionsCompile) error {
-	image := DockerDefaultImage
+	args := d.args()
-	if d.Image != "" {
-		image = d.Image
-	}
-
-	// Argument -i is needed for stdio to work.
-	args := []string{"run", "-i"}
-
-	// Add mounts.
-	for _, volume := range d.Volumes {
-		args = append(args, "-v", volume)
-	}
-
-	args = append(args, image)
 
 	// From here on come Typst arguments.
 
-	args = append(args, "c")
+	if options == nil {
-	if options != nil {
+		options = new(OptionsCompile)
-		args = append(args, options.Args()...)
 	}
-	args = append(args, "--diagnostic-format", "human", "-", "-") // TODO: Move these default arguments into Options
+	args = append(args, options.Args()...)
 
 	cmd := exec.Command("docker", args...)
 	cmd.Dir = d.WorkingDirectory

options.go

@@ -57,6 +57,9 @@ type OptionsFonts struct {
 
 // Args returns a list of CLI arguments that should be passed to the executable.
 func (o *OptionsFonts) Args() (result []string) {
+	// The first argument is the command we want to run.
+	result = []string{"fonts"}
+
 	if len(o.FontPaths) > 0 {
 		var paths string
 		for i, path := range o.FontPaths {
@@ -118,6 +121,9 @@ type OptionsCompile struct {
 
 // Args returns a list of CLI arguments that should be passed to the executable.
 func (o *OptionsCompile) Args() (result []string) {
+	// The first argument is the command we want to run.
+	result = []string{"c"}
+
 	if o.Root != "" {
 		result = append(result, "--root", o.Root)
 	}
@@ -194,7 +200,15 @@ func (o *OptionsCompile) Args() (result []string) {
 		result = append(result, "--pdf-standard", standards)
 	}
 
+	// Use human diagnostic format, as that's the format that we support right now.
+	// TODO: Switch to a different diagnostic format in the future
+	result = append(result, "--diagnostic-format", "human")
+
 	result = append(result, o.Custom...)
 
+	// Use stdio for input and output.
+	// TODO: Add Args parameters for when we want to use files instead
+	result = append(result, "-", "-")
+
 	return
 }

options_test.go

@@ -1,29 +0,0 @@
-// Copyright (c) 2025 David Vogel
-//
-// This software is released under the MIT License.
-// https://opensource.org/licenses/MIT
-
-package typst_test
-
-import (
-	"os"
-	"testing"
-
-	"github.com/Dadido3/go-typst"
-)
-
-func TestOptions(t *testing.T) {
-	o := typst.OptionsCompile{
-		FontPaths: []string{"somepath/to/somewhere", "another/to/somewhere"},
-	}
-	args := o.Args()
-	if len(args) != 2 {
-		t.Errorf("wrong number of arguments, expected 2, got %d", len(args))
-	}
-	if args[0] != "--font-path" {
-		t.Error("wrong font path option, expected --font-path, got", args[0])
-	}
-	if args[1] != "somepath/to/somewhere"+string(os.PathListSeparator)+"another/to/somewhere" {
-		t.Error("wrong font path option, expected my two paths concatenated, got", args[1])
-	}
-}